Method for producing a semiconductor

ABSTRACT

A method for producing a semiconductor is disclosed. One embodiment provides a p-doped semiconductor body having a first side and a second side. An n-doped zone is formed in the semiconductor body by implantation of protons into the semiconductor body via the first side down to a specific depth of the semiconductor body and by subsequent heating at least of the proton-implanted region of the semiconductor body. A pn junction arises in the semiconductor body. The second side of the semiconductor body is removed at least as far as a space charge zone spanned at the pn junction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Utility patent application claims priority to German PatentApplication No. DE 10 2008 025 733.8 filed on May 29, 2008, which isincorporated herein by reference.

BACKGROUND

One embodiment of the invention relates to a method for producing a thinsemiconductor body and to the use of the method for producing a powersemiconductor component.

For a multiplicity of applications of electronic semiconductorcomponents and integrated circuits (IC), it is advantageous to restrictthe total thickness of the semiconductor components and of theintegrated circuits. Thus, for example, in disposable electronics andfor chip cards and smart cards, a very small mass and a very smallstructural height are of importance. By using targeted settings of thethickness of the semiconductor body used, the electrical properties ofe.g., vertical power semiconductor components can be improved byadapting the thickness of the semiconductor body to the voltage class ofthe respective power semiconductor component, in order to avoidunnecessary electrical resistance through over-dimensioned semiconductorbodies.

However, this necessitates a very precise and reproducible thicknesssetting over the entire area of the semiconductor body used, in order toavoid losses of yield in production and in order to ensure reliableelectrical properties of the semiconductor component and of theintegrated circuit.

For these and other reasons, there is a need for the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of embodiments and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments andtogether with the description serve to explain principles ofembodiments. Other embodiments and many of the intended advantages ofembodiments will be readily appreciated as they become better understoodby reference to the following detailed description. The elements of thedrawings are not necessarily to scale relative to each other. Likereference numerals designate corresponding similar parts.

FIGS. 1A and 1B schematically illustrate one embodiment of a method forthinning a semiconductor body.

FIG. 2 illustrates one embodiment of a doping profile of an n-typedopant after one proton implantation with subsequent heating in ap-doped semiconductor body.

FIG. 3 illustrates one embodiment of a doping profile of an n-typedopant after two proton implantations with subsequent heating in ap-doped semiconductor body.

FIG. 4 illustrates one embodiment of a doping profile of an n-typedopant after two proton implantations with subsequent heating in ap-doped semiconductor body.

FIG. 5 illustrates one embodiment of a doping profile of a semiconductorbody for a power semiconductor component.

FIG. 6 illustrates a schematic cross-sectional view of a powersemiconductor component with a semiconductor body.

FIG. 7 illustrates a schematic arrangement for the electrochemicaletching of a semiconductor body with a pn junction.

DETAILED DESCRIPTION

In the following Detailed Description, reference is made to theaccompanying drawings, which form a part hereof, and in which is shownby way of illustration specific embodiments in which the invention maybe practiced. In this regard, directional terminology, such as “top,”“bottom,” “front,” “back,” “leading,” “trailing,” etc., is used withreference to the orientation of the Figure(s) being described. Becausecomponents of embodiments can be positioned in a number of differentorientations, the directional terminology is used for purposes ofillustration and is in no way limiting. It is to be understood thatother embodiments may be utilized and structural or logical changes maybe made without departing from the scope of the present invention. Thefollowing detailed description, therefore, is not to be taken in alimiting sense, and the scope of the present invention is defined by theappended claims.

It is to be understood that the features of the various exemplaryembodiments described herein may be combined with each other, unlessspecifically noted otherwise.

Before the exemplary embodiments are explained in more detail below withreference to the figures, it is pointed out that identical elements areprovided with the same or similar reference symbols in the Figures andthat a repeated description of these elements is omitted. Furthermore,the Figures are not necessarily true to scale; rather, the main emphasisis on elucidating the basic principle.

The term pn junction is defined hereinafter as the location in asemiconductor body at which an n-type dopant concentration N_(D) of thesemiconductor body falls below a p-type dopant concentration N_(A) ofthe semiconductor body or a p-type dopant concentration N_(A) fallsbelow an n-type dopant concentration N_(D) of the semiconductor body.

One or more embodiments provide a method for producing a semiconductorbody which permits an exact and reproducible thinning of thesemiconductor body, and the use of this method for producing powersemiconductor components.

FIG. 1A illustrates a semiconductor body 10 having a first side 11 and asecond side 12, wherein the direction leading from the first side 11 tothe second side 12 is designated as the y-direction. The semiconductorbody 10 is typically a semiconductor wafer. Such wafers are normallystarting products for the mass production of semiconductor componentsand are available in sizes of currently approximately 750 μm thickness(y-direction) and up to 300 mm diameter (x-direction). The startingsemiconductor body 10 used here is doped with a p-type dopant, such thatthe semiconductor body has a p-type basic doping. The electricalconductivity of the semiconductor body 10 is therefore initiallydetermined by “holes” (p-type charge carriers) as majority carriers. Toa certain extent, but with a significantly lower concentration, however,the semiconductor body also already contains conduction electrons(n-type charge carriers) as minority carriers.

Silicon is principally suitable as semiconductor material for thesemiconductor body 10. The sheet resistance of the p-doped semiconductorbody lies between 100 Ohm cm and 5000 Ohm cm, for example. Asillustrated in subprocess a) in FIG. 1, protons 14 are implanted intothe semiconductor body 10 at the first side 11. Afterward, at least thatregion of the semiconductor body 10 which has been implanted withprotons 14 is subjected to heat treatment, that is to say heated andheld at this temperature level for a specific time. This gives rise toan n-doped zone 10 a and accordingly a pn junction 13 in the p-dopedsemiconductor body 10. In one embodiment, the n-doped zone 10 a isproduced with a proton irradiation dose of between 10¹⁴ cm⁻² and 10¹⁵cm⁻².

Embodiments relate generally to a method for producing a semiconductorbody, wherein a p-doped semiconductor body having a first side and asecond side is provided, an n-doped zone is formed in the semiconductorbody by implantation of protons into the semiconductor body via thefirst side down to a specific depth of the semiconductor body and bysubsequent heating at least of the proton-implanted region of thesemiconductor body, such that a pn junction arises in the semiconductorbody, and the second side of the semiconductor body is removed at leastas far as a space charge zone spanned at the pn junction.

One or more embodiments provide a use of the method for producing thesemiconductor body for producing a power semiconductor component,wherein in each case at least one electrode is fitted to the first andto the second side of the semiconductor body produced.

The proton irradiation with subsequent heating makes it possible toproduce an n-doped zone and thus a pn junction at an exactly predefinedlocation homogeneously also over a large area in the semiconductor body.As a result of the high penetration depth of protons into asemiconductor body, the pn junction can also be produced at a largedepth in the semiconductor body, which cannot be realized byconventional implantation or diffusion techniques. The space charge zonespanned at the pn junction or the pn junction itself can be used for aprecise ending of the rear-side removal of the original semiconductorbody, thereby enabling an exact and reproducible thinning of thesemiconductor body to a desired and predetermined final thickness.

FIG. 1B illustrates an n-doped zone 10 a formed in this way and the pnjunction 13 in the semiconductor body 10 in subprocess b). The energy ofthe proton radiation 14 is set in such a way that the pn junction 13 isproduced at a predetermined location in the semiconductor body 10. Inone embodiment, the position of the pn junction is determined accordingto the desired final thickness of the semiconductor body 10. Embodimentsof the invention provide for the pn junction 13 to be produced at adepth T of 20 μm to 350 μm, measured from the surface of the first side11. In the case of a silicon semiconductor body, the proton radiationenergy here lies in the range of between 1 MeV and 8 MeV. In principlethe proton radiation energy correlates with the penetration depth of theprotons into the semiconductor material used. The higher the protonradiation energy used, the larger the penetration depth of the protonsinto the semiconductor material used.

The heating (heat treatment) of the semiconductor body 10 that iseffected after the proton irradiation in one or more embodimentsincludes an annealing phase in the range of between 350° C. and 550° C.,since the hydrogen-induced n-type doping forms in this temperaturerange. In one embodiment, the annealing phase is effected attemperatures of between 450° C. and 520° C. In one embodiment, theannealing phase is carried out for at least 15 minutes and can also takeplace over a number of hours.

After the formation of the n-doped zone 10 a and the pn junction 13, inthermodynamic equilibrium as a result of diffusion of charge carriersacross the pn junction 13, a space charge zone 15 forms as far as aboundary 15″ in the n-doped zone 10 a and as far as a boundary 15′ inthe remaining p-doped semiconductor body 10 b, since a highconcentration difference in the carrier densities exists between then-doped zone 10 a and the remaining p-doped semiconductor body 10 b. Asa result of the fixed charges remaining, the previously electricallyneutral crystals have now acquired a space charge that charges thep-type crystal negatively and the n-type crystal positively. Theresultant electrical voltage is called the diffusion voltage U_(D).

By applying an external bias voltage across the pn junction 13, theboundaries 15′ and 15″ can be displaced and the width W of the spacecharge zone can thus be controlled. By applying the external biasvoltage in the reverse direction of the pn junction 13 (+ at the n-dopedzone 10 a, − at the remaining p-doped semiconductor body 10 b), by wayof example, the width W of the space charge zone 15 is increased. If theexternal bias voltage is polarized in the forward direction of the pnjunction 13 (−at the n-doped zone 10 a, + at the remaining p-dopedsemiconductor body 10 b), the width W of the space charge zone 15 isdecreased. As soon as the external bias voltage with polarization in theforward direction is greater than or equal to the diffusion voltage, thespace charge zone 15 is dissolved, that is to say that the boundaries15′ and 15″ fall on top of one another and the width W of the spacecharge zone is equal to zero.

After the formation of pn junction 13 and a space charge zone 15 thatpossibly occurs, the semiconductor body 10 is thinned. In the case wherea space charge zone 15 is spanned at the pn junction 13, this takesplace by removing the second side 12 of the semiconductor body 10 in thenegative y-direction as far as the space charge zone 15, that is to sayas far as the boundary 15′ of the space charge zone 15 that is situatedin the residual p-doped semiconductor body 10 b, as is illustrated byarrows 16 in FIG. 1B. Consequently, a region 10 b″ of the semiconductorbody is removed, while a residue 10 b′ of the p-doped semiconductor body10 remains in the thinned state at the second side. By way of example,by using suitable setting of the bias voltage value across the pnjunction, the space charge zone can be extended up to 5 μm into theresidual p-doped semiconductor body, which results in a correspondinglythick p-doped residual layer 10 b′ after the thinning. In the case of adissolved space charge zone 15, the second side is removed as far as thepn junction 13, that is to say that the residue 10 b of the p-dopedsemiconductor body that remained from the original semiconductor body 10after the production of the n-doped zone 10 a is completely removed. Theremoval of the second side 12 can in any case be effected in a locallydelimited manner by using masks, for example, or else over the wholearea over the entire semiconductor body 10. The removal is generallyeffected at least in part by using an electrochemical etching methodwherein the boundary 15″ of the space charge zone or, in the absence ofa space charge zone, the pn junction is used as an “etching stop” forending the etching process. When this “etching stop” is reached, theetching process automatically terminates; in other words, the etchingstop is effected in a self-aligned manner in this way. A very exactremoval of the second side 12 of the semiconductor body 10 is thuspossible. By way of example, a characteristic change in a currentflowing within the electrochemical etching apparatus is measured whenthe “etching shop” is reached, which is used for ending the etchingprocess. Mechanical removal methods can also be used at the beginning ofthe removal of the second side 12 of the semiconductor body 10.

FIG. 2 illustrates one embodiment of a doping profile of an n-doped zone10 a produced according to the method described above in a p-dopedsemiconductor body 10. The n-doped zone 10 a extends from the surface ofthe first side 11 of the semiconductor body 10 as far as the pn junction13 at a depth T into the semiconductor body 10. The n-doped zone 10 ahas a region N1 having a virtually constant n-type dopant concentrationN_(D), that is to say that the n-doped dopant concentration N_(D)changes typically by at most a factor of 3 in the region N1. The regionN1 extends within the n-doped zone 10 a from the surface of the firstside 11 as far as the depth A. Typical values for A are in this case 15μm<A<300 μm. Between the region N1 and the pn junction 13, a region N2extends in the n-doped zone 10 a, the region N2 having a n-type dopantmaximum N_(Dmax) at the depth B in the semiconductor body 10. In thiscase, the n-type dopant maximum N_(Dmax) is produced at the location ofthe highest proton density originating from the proton implantation. Onaccount of the—in the case of protons—very small variation range of thepenetration depth into the semiconductor body 10, the location havingthe highest proton density is situated virtually at the pn junction 13(“End-of-Range”). The n-type dopant concentration N_(D) thus falls verysteeply from the n-type dopant maximum N_(Dmax) toward the pn junction13. The “End-of-Range” region forms the end of the region which isirradiated by the proton implantation and in which the majority of theprotons is incorporated during the implantation. On account of theannealing process, a large portion of the protons diffuses in thenegative y-direction toward the first side 11, which results in thedoping N_(D) in the region through which the protons are radiated. Theprotons that diffuse into the depth of the p-type semiconductor body 10in the positive y-direction toward the second side 12 do not lead to theformation of donors in this region, since implantation-induced crystaldefects required therefor are not present there. The difference betweenthe maximum doping concentration N_(Dmax) in the “End-of-Range” regionand the doping concentration N_(D) in the n-doped zone 10 a is dependenton the temperature during the thermal process and the duration of thethermal process. It holds true here that for the same duration of thethermal process, the difference is all the smaller, the higher thetemperature during the thermal process, and that for a given temperatureduring the thermal process, the difference is all the smaller, thelonger the duration of the thermal process. The energy of the protonirradiation, the proton dose and the annealing temperature and annealingtime are chosen so as to produce a sufficient n-type doping maximumN_(Dmax) e.g., for a field stop zone and for forming a pn junction, onthe one hand, and for forming a suitable basic doping N_(D) of then-doped zone 10 a, on the other hand. The n-type basic doping N_(D) ofthe n-doped zone 10 a can be produced without additional outlay from theproduction of the pn junction required for the thinning of thesemiconductor body 10. In a form that is not illustrated, the n-typedopant maximum N_(Dmax) can be completely reduced by a sufficiently longannealing phase of the proton-implanted region over e.g., a number ofhours and can be converted into a virtually constant n-type dopantconcentration N_(D), with the result that the homogeneous region N1extends from the surface of the first side 11 to shortly before the pnjunction 13. However, the n-doped zone 10 a can also be produced with ann-type dopant concentration N_(D) that falls from the n-type dopantmaximum N_(Dmax) in the direction toward the first side 11 of thesemiconductor body 10.

The p-doped residue 10 b of the semiconductor body 10 that remains fromthe original semiconductor body 10 extends from the pn junction 13 asfar as the surface of the second side 12 and has a largely constantp-type dopant concentration N_(A).

FIG. 3 illustrates one embodiment of a doping profile of an n-doped zone10 a produced according to one embodiment in a p-doped semiconductorbody 10. In contrast to the doping profile illustrated in FIG. 2, thedepth B of an n-type dopant maximum N_(Dmax) produced in the n-dopedzone 10 a is spaced apart further from the pn junction 13. However, asin the exemplary embodiment regarding FIG. 2 as well, the n-type dopantmaximum N_(Dmax) is still situated nearer to pn junction 13 than to thesurface of the first side 11 of the semiconductor body 10 in the regionN2. A region N3 having a reduced n-type dopant concentration N_(D) isadditionally formed between the n-type dopant maximum N_(Dmax) and thepn junction 13, wherein the region N3 as illustrated, can have a“shoulder” 30 having an n-type dopant concentration N_(D) that isvirtually constant over a length 1. This “shoulder” 30 produced over thelength 1 in the region N3 has, for example, a higher n-type dopantconcentration N_(D) than the region N1. The “shoulder” 30 is defined asthe region in which the n-type dopant concentration changes (ΔN) at mostby a factor of 3. The n-type dopant concentration N_(D) in the region ofthe shoulder 30 should, but need not necessarily, be lower than that ofthe n-type dopant maximum N_(Dmax) at least by a factor of 5. The length1 of the shoulder can be, for example, between 1 μm and 20 μm.

As illustrated in FIG. 4, a region having an n-type dopant minimumN_(Dmin) can also be present between the shoulder 30 having anapproximately constant n-type dopant concentration N_(D) and the regionN2, wherein the concentration of the n-type dopant minimum N_(Dmin) canbe lower than the dopant concentration N_(D) in the region of theshoulder 30, for example, by more than a factor of 3.

The region N3 that has a shoulder and is illustrated by way of examplein FIG. 3 and FIG. 4 makes it possible to set a well-defined distancebetween the n-type dopant maximum N_(Dmax) in the region N2 and the pnjunction 13. Consequently, it is possible to set e.g., a very readilyreproducible efficiency of a rear-side emitter introduced into the wafersurface, which, moreover, can have a relatively small currentdependence.

The doping profile illustrated in FIG. 3 and FIG. 4 can be produced, forexample, by using a first proton implantation into the p-dopedsemiconductor body 10 with a subsequent annealing phase over a long timeperiod and a succeeding further proton implantation with an increasedimplantation energy and decreased implantation dose relative to thefirst proton implantation. In this case, the duration and thetemperature of the annealing phase of the first proton implantation isstill chosen to be sufficiently short and low, respectively, that then-type dopant maximum N_(Dmax) remains in the region N2 of the n-dopedzone 10 a. The second proton implantation is likewise carried out viathe first side 11 of the semiconductor body 10 and annealed, wherein theduration and temperature of this annealing phase are chosen such thatthe “shoulder” 30 is formed. The n-type dopant minimum N_(Dmin) in FIG.4 can be produced by short annealing times of the second protonimplantation. The diffusion of the implanted protons in the direction ofthe n-type dopant maximum N_(Dmax) then extends only as far as then-type dopant minimum N_(Dmin).

FIG. 5 illustrates one embodiment of a doping profile of a semiconductorbody for a power semiconductor component. The semiconductor body isproduced by forming an n-doped zone 10 a by using proton implantationand subsequent thinning, as already explained regarding FIG. 1. In thiscase, the second side 12 is removed as far as the boundary 15′ of aspace charge zone at the pn junction 13, which is situated, for example,approximately 5 μm in the residual p-doped residue 10 b of thesemiconductor body as a result of the application of a bias voltagepolarized in the reverse direction. As a result of the removal of thesecond side 12, one part 10 b″ of the p-doped residue 10 b of thesemiconductor body 10 is removed, while another part 10 b′ of thep-doped residue 10 b remains. The part 10 b′ has a thickness ofapproximately 5 μm corresponding to the position of the boundary 15′.

At the thinned second side 12 of the semiconductor body 10, anadditional p-type doping near the surface is then carried out byindiffusion or implantation in combination with a thermal activation orindiffusion of the implanted atoms of p-type dopant. The resultant“rear-side” highly doped P-type zone 40 can be used, for example, as ap-type emitter for an IGBT.

At the first side 11 of the semiconductor body 10, a p-type doping intothe n-doped zone 10 a—which initially reaches as far as the surface ofthe first side 11—is likewise carried out by using diffusion orimplantation of p-type dopant, to be precise, for example, before theproton implantation described above is carried out and before thethinning process described. This gives rise to a p-doped zone 41 which,at the surface of the first side 11, reaches down to a depth C andwhich, together with the n-doped zone 10 a, forms a further pn junctionat a depth C near the surface at the first side of the semiconductorbody.

FIG. 6 illustrates a power semiconductor component 200. Thesemiconductor component 200 has a thinned semiconductor body 10 producedaccording to an embodiment of the method described above. An electrode20 is fitted to the surface in each case of the first side 11 and of thesecond side 12 of the semiconductor body 10.

The semiconductor component 200 can be any vertical semiconductorcomponent, that is to say a semiconductor component whose currentconduction takes place from the first side transversely through thethickness of the semiconductor body 10 to the second side in they-direction. In one embodiment, it can be an IGBT, a diode or athyristor.

The region N2 having the n-type doping maximum N_(Dmax) described in theprevious exemplary embodiments can be used as a field stop zone, forexample, in the case of an IGBT. The n-type doping maximum N_(Dmax)produced by proton irradiation with subsequent heat treatment can bealigned very exactly to the surface of the second side 12. By virtue ofthe high proton radiation energy required for producing the n-typedopant maximum N_(Dmax) near to the surface of the second side 12 of thesemiconductor body 10 via the first side 11 of the semiconductor body10, it is possible to radiate through any defects or impurities in or onthe semiconductor body without any problems. Consequently, it ispossible to set the position of the field stop exactly with respect tothe surface of the second side 12 of the semiconductor body 10, whichenables a precise setability and high reproducibility of the gain factorα_(pnp) of the collector-side partial transistor of the IGBT. A greatvariation of the electrical properties of the semiconductor component200 is thus avoided. Moreover, the very small and well-defineddistance—thus possible—of below 5 μm between the field stop zone and therear-side emitter at the second side 12 ensures a high and reproducibleshort-circuit strength, a desirable softness when turning off thesemiconductor component 200 and avoidance of particle-governed leakagecurrent problems.

The n-doped zone 10 a which is produced by using the method explainedabove and has an n-type doping with hydrogen-induced donors is suitablein one embodiment for realizing a semiconductor zone of a powersemiconductor component that takes up a reverse voltage. Such a zone is,for example, the drift zone of a MOSFET, the drift zone or n-type baseof an IGBT, or the drift zone or n-type base of a diode.

FIG. 7 is a schematic illustration of a setup for the electrochemicaletching of a p-doped semiconductor body 10 having an n-doped zone 10 aand a pn junction 13. An etching cell 600 of the setup includes at leastan anode, a cathode 61 and an aqueous alkaline solution 60. The anode isformed by the n-doped zone 10 a of the semiconductor body 10 to bethinned, at which a positive potential is present. The cathode 61 is aplatinum electrode, for example, at which a negative potential ispresent. Both the anode and thus the semiconductor body 10 having then-doped zone 10 a and the pn junction 13 and the cathode 61 are immersedin the aqueous alkaline solution 60.

Further embodiments of the etching cell 600 can, for example, also haveother etching solutions such as, for example, a pure potassium hydroxidesolution (KOH), ethylenediamine (EDP) or hydrazine-water solutions.Further embodiments can also have three or more electrodes. The positivepotential can be applied to the contact-connection of the anode, in thepresent case of the n-doped zone 10 a, by using suitable contactstructures such as, for example, a net-like contact structure.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat a variety of alternate and/or equivalent implementations may besubstituted for the specific embodiments shown and described withoutdeparting from the scope of the present invention. This application isintended to cover any adaptations or variations of the specificembodiments discussed herein. Therefore, it is intended that thisinvention be limited only by the claims and the equivalents thereof.

1. A method for producing a semiconductor, comprising: providing ap-doped semiconductor body having a first side and a second side;forming an n-doped zone in the semiconductor body by implantation ofprotons into the semiconductor body via the first side down to aspecific depth of the semiconductor body and by subsequent heating atleast of the proton-implanted region of the semiconductor body, suchthat a pn junction arises in the semiconductor body; and removing thesecond side of the semiconductor body at least as far as a space chargezone spanned at the pn junction.
 2. The method of claim 1, comprisingeffecting the implantation of the protons with an implantation energylying in the range of between 1 MeV and 8 MeV.
 3. The method of claim 1,comprising producing the pn junction at a depth T in the range of 20 μmto 350 μm, measured from a surface of the first side.
 4. The method ofclaim 1, wherein the heating comprises an annealing phase in atemperature range of between 350° C. and 550° C.
 5. The method of claim1, wherein the heating includes an annealing phase in a temperaturerange of between 450° C. and 520° C.
 6. The method of claim 4,comprising wherein the annealing phase has a duration of at least 15min.
 7. The method of claim 1, comprising forming the space charge zoneby diffusion of charge carriers across the pn junction.
 8. A method forproducing a semiconductor comprising: forming the space charge zone byapplying a bias voltage across the pn junction providing a p-dopedsemiconductor body having a first side and a second side; forming ann-doped zone in the semiconductor body by implantation of protons intothe semiconductor body via the first side down to a specific depth ofthe semiconductor body and by subsequent heating at least of theproton-implanted region of the semiconductor body, such that a pnjunction arises in the semiconductor body; and removing the second sideof the semiconductor body at least as far as a space charge zone spannedat the pn junction.
 9. The method of claim 8, comprising setting a widthW of the space charge zone by setting a specific bias voltage valueacross the pn junction.
 10. The method of claim 8, comprising polarizingthe bias voltage across the pn junction in the forward direction of thepn junction.
 11. The method of claim 10, comprising wherein the biasvoltage is greater than a diffusion voltage UD of the space charge zoneacross the pn junction, with the result that the space charge zone isdissolved.
 12. The method of claim 11, comprising wherein the removal ofthe second side ends at the pn junction.
 13. The method of claim 8,comprising polarizing the bias voltage across the pn junction in thereverse direction of the pn junction.
 14. The method of claim 13,comprising setting the bias voltage value such that the space chargezone extends between 0.5 μm and 5 μm into the p-doped semiconductorbody.
 15. The method of claim 14, comprising effecting at least a lastpart of the removal of the second side by electrochemical etching.
 16. Amethod for producing a semiconductor comprising: producing an n-typedoping maximum in the n-doped zone providing a p-doped semiconductorbody having a first side and a second side; forming an n-doped zone inthe semiconductor body by implantation of protons into the semiconductorbody via the first side down to a specific depth of the semiconductorbody and by subsequent heating at least of the proton-implanted regionof the semiconductor body, such that a pn junction arises in thesemiconductor body; and removing the second side of the semiconductorbody at least as far as a space charge zone spanned at the pn junction.17. The method of claim 16, comprising producing the n-type dopingmaximum nearer to the pn junction than to the surface of the first sideof the semiconductor body.
 18. The method of claim 16, comprisingproducing the n-type doping maximum by a further proton implantationwith subsequent heating.
 19. The method of claim 18, comprisingeffecting the further proton implantation via the first side of thesemiconductor body.
 20. The method of claim 16, comprising producing aregion having a virtually constant n-type doping concentration NDbetween the n-type doping maximum and the surface of the first side ofthe semiconductor body in the n-doped zone.
 21. The method of claim 16,comprising producing a region having an n-type dopant minimum betweenthe n-type doping maximum and the pn junction in the n-doped zone. 22.The method of claim 16, comprising forming an n-doped shoulder in aregion between the n-type doping maximum and the pn junction in then-doped zone, wherein in the shoulder the n-type doping concentration NDchanges by at most a factor of 3 over a length of 1 to 5 μm.
 23. Themethod of claim 22, comprising producing the n-doped zone with a protonirradiation dose of between 1014 cm−2 and 1015 cm−2.
 24. The method ofclaim 23, comprising wherein the semiconductor body is a silicon wafer.25. A method comprising: producing a power semiconductor componentcomprising: providing a p-doped semiconductor body having a first sideand a second side; forming an n-doped zone in the semiconductor body byimplantation of protons into the semiconductor body via the first sidedown to a specific depth of the semiconductor body and by subsequentheating at least of the proton-implanted region of the semiconductorbody, such that a pn junction arises in the semiconductor body; andremoving the second side of the semiconductor body at least as far as aspace charge zone spanned at the pn junction; and fitting at least oneelectrode the first side and the second side of the semiconductor body.